CN-122025395-A - Magnetic element and method for producing the same

CN122025395ACN 122025395 ACN122025395 ACN 122025395ACN-122025395-A

Abstract

The invention relates to the technical field of magnetic materials, in particular to a magnetic element and a preparation method thereof, wherein the preparation method of the magnetic element comprises the following steps: and uniformly mixing a binder and magnetic particles, and then curing, wherein the magnetic particles are iron-based nanocrystals with a plurality of median particle sizes and metal soft magnetic particles with a plurality of median particle sizes, the minimum median particle size of the iron-based nanocrystals is larger than the maximum median particle size of the metal soft magnetic particles, and the metal soft magnetic particles comprise one or more of FeNi alloy particles and FeCo alloy particles. In the field of medium-frequency application, the magnetic permeability and the resistivity of the magnetic element can be improved by mixing the two components, so that the magnetic element has high magnetism and low loss. The median particle diameter of the magnetic particles realizes near gradient distribution, and the grading mode can further improve the stacking density of the magnetic particles in the magnetic element, reduce the porosity of the magnetic element, improve the density of the magnetic element and further improve the magnetic permeability of the magnetic element.

Inventors

ZHU HANGFEI
WANG LEIJIE
ZHANG NING
SHAN ZHEN
CAI LINGWEN

Assignees

横店集团东磁股份有限公司
金华市磁盟知识产权服务有限公司

Dates

Publication Date: 20260512
Application Date: 20251231

Claims (10)

1. A preparation method of a magnetic element is characterized by comprising the steps of uniformly mixing a binder and magnetic particles, and then solidifying, wherein the magnetic particles are iron-based nanocrystals with a plurality of median particle diameters and metal soft magnetic particles with a plurality of median particle diameters, the minimum median particle diameter of the iron-based nanocrystals is larger than the maximum median particle diameter of the metal soft magnetic particles, and the metal soft magnetic particles comprise one or more of FeNi alloy particles and FeCo alloy particles.
2. The method of claim 1, wherein the iron-based nanocrystals have a median particle size of 5-50 μm; and/or the median particle diameter of the metal soft magnetic particles is 1 μm to 30 μm; And/or the magnetic particles have a first median particle diameter from large to small to an nth median particle diameter, N is an integer greater than or equal to 4, N is an integer greater than or equal to 1 and less than or equal to N-1, and the difference between the nth median particle diameter and the n+1th median particle diameter is 1 μm to 15 μm; And/or the mass ratio of the binder to the magnetic particles is 1% -3%; And/or the mass ratio of the iron-based nanocrystalline to the metal soft magnetic particles is 1 (0.2-5).
3. The preparation method according to claim 2, wherein the iron-based nanocrystals include a first iron-based nanocrystal and a second iron-based nanocrystal, the median particle diameter of the first iron-based nanocrystal is larger than the median particle diameter of the second iron-based nanocrystal, and the mass ratio of the first iron-based nanocrystal to the second iron-based nanocrystal is 1 (0.5-2); And/or the metal soft magnetic particles comprise first metal soft magnetic particles and second metal soft magnetic particles, the median particle size of the first metal soft magnetic particles is larger than that of the second metal soft magnetic particles, and the mass ratio of the first metal soft magnetic particles to the second metal soft magnetic particles is 1 (0.5-2).
4. A process according to any one of claims 1 to 3, wherein the iron-based nanocrystals have a sphericity of 90% or more and the metal soft magnetic particles have a sphericity of 90% or more and/or, The iron-based nanocrystalline includes one or more of FeSiBCu nanocrystalline, feSiBCuNb nanocrystalline, feCoSiBCuNb nanocrystalline, and/or, The binder comprises one or more of phenolic resin, epoxy resin and polyamide resin.
5. The method according to any one of claims 1 to 4, wherein the step of uniformly mixing the binder and the magnetic particles and then curing the mixture comprises: Wet-milling and mixing the iron-based nanocrystalline and the metal soft magnetic particles to obtain a magnetic mixture; adding the magnetic mixture into a dispersing agent solution for ball milling; Removing the solvent of the dispersant solution in the ball milling product to obtain a solid mixture; Dispersing the solid mixture in a binder solution, and removing a solvent of the binder solution to obtain slurry; And after the slurry is subjected to first curing, sequentially performing pressing and second curing, wherein the temperature of the second curing is higher than that of the first curing.
6. The method of claim 5, wherein the mass ratio of dispersant in the dispersant solution to the magnetic mixture is 0.1% -0.3%; And/or, in the ball milling process, the rotating speed is 40r/min-60r/min, and the time is 10min-20min; and/or the temperature of the first curing is 60-100 ℃ and the time is 2-4 h; And/or the temperature of the second curing is 150-250 ℃ for 1-6 hours; And/or the pressure during the pressing is 6T/cm 2 -15T/cm 2 .
7. The method according to claim 5 or 6, further comprising ultrasonically vibrating and dispersing the ball-milled product before removing the solvent of the dispersant solution in the ball-milled product.
8. The method according to any one of claims 5 to 7, further comprising dispersing the solid mixture into a surface modifier solution before dispersing the solid mixture in a binder solution, and removing a solvent of the surface modifier solution; preferably, the ratio of the mass of surface modifier in the surface modifier solution to the mass of the magnetic mixture is 0.1% to 0.3%; Preferably, the surface modifier comprises one or more of chromic acid, phosphoric acid, sodium silicate, sodium tetraborate, aminosilane, epoxysilane, and vinylsilane.
9. The method according to any one of claims 5 to 8, further comprising sieving the slurry before the first curing is performed; Preferably, the mesh number of the screen is 40-80 mesh.
10. A magnetic element prepared by the preparation method according to any one of claims 1 to 9.

Description

Magnetic element and method for producing the same Technical Field The invention relates to the technical field of magnetic materials, in particular to a magnetic element and a preparation method thereof. Background Nanocrystalline is used as a representative of modern magnetic functional materials, and innovations in the fields of power electronics, new energy, aerospace and the like are being promoted by virtue of the unique microstructure and excellent electromagnetic properties of nanocrystalline. Along with the upgrading of electronic information industry, the nanocrystalline is continuously broken through in key links such as energy conversion efficiency improvement, equipment miniaturization, electromagnetic compatibility design and the like. However, in the field of mid-frequency application, the nanocrystalline material has high resistivity, can inhibit eddy current loss, but has the problem of low magnetic permeability, i.e. cannot have both high magnetic permeability and high resistivity. Disclosure of Invention In view of the above, the present invention provides a magnetic element and a method for manufacturing the same, so as to improve the magnetic permeability and the electrical resistivity of the magnetic element. In a first aspect, the invention provides a method for preparing a magnetic element, which comprises the steps of uniformly mixing a binder and magnetic particles, and then solidifying, wherein the magnetic particles are iron-based nanocrystals with a plurality of median particle diameters and metal soft magnetic particles with a plurality of median particle diameters, the minimum median particle diameter of the iron-based nanocrystals is larger than the maximum median particle diameter of the metal soft magnetic particles, and the metal soft magnetic particles comprise one or more of FeNi alloy particles and FeCo alloy particles. In the field of medium-frequency application, feNi alloy and FeCo alloy have higher magnetic permeability but higher eddy current loss, and nanocrystalline has high resistivity, can inhibit the eddy current loss, but has lower magnetic permeability. The two materials are mixed and used, so that the defect of single material can be overcome, the magnetic conductivity and the resistivity of the magnetic element are improved, and the magnetic element has high magnetism and low loss. The iron-based nanocrystalline and the metal soft magnetic particles are provided with a plurality of median particle sizes, and the minimum median particle size of the iron-based nanocrystalline is larger than the maximum median particle size of the metal soft magnetic particles, so that the median particle sizes of the magnetic particles are distributed in a near gradient mode. The magnetic field is changed, the magnetic field is applied to the magnetic element, the coercivity of the large particles is smaller than that of the small particles, the magnetic field can be quickly responded, hysteresis loss of the magnetic element is reduced, insulating adhesive is arranged on the outer surfaces of the small particles, the number of boundaries of particles in the magnetic element can be increased by the small particles, thus eddy current loops are effectively divided, the eddy current loops are smaller, the eddy current strength is weaker, the loss is lower, and the eddy current loss of the magnetic element is further effectively reduced. In some alternative embodiments, the iron-based nanocrystals have a median particle size of from 5 μm to 50 μm. In some alternative embodiments, the metal soft magnetic particles have a median particle diameter of 1 μm to 30 μm. In some alternative embodiments, the magnetic particles have a first median particle size from large to small to an nth median particle size, N is an integer greater than or equal to 4, N is an integer greater than or equal to 1 and less than or equal to N-1, and the difference between the nth median particle size and the n+1th median particle size is 1 μm to 15 μm. In some alternative embodiments, the ratio of the mass of the binder to the mass of the magnetic particles is 1% -3%. In some alternative embodiments, the ratio of the mass of the iron-based nanocrystalline to the mass of the metallic soft magnetic particles is 1 (0.2-5). In some alternative embodiments, the iron-based nanocrystals include a first iron-based nanocrystal and a second iron-based nanocrystal, the median particle size of the first iron-based nanocrystal being greater than the median particle size of the second iron-based nanocrystal, the ratio of the masses of the first iron-based nanocrystal to the second iron-based nanocrystal being 1 (0.5-2). In some alternative embodiments, the metal soft magnetic particles comprise first metal soft magnetic particles and second metal soft magnetic particles, the median particle size of the first metal soft magnetic particles is greater than the median particle size of the second metal soft magnetic particles,